THE farm crisis in the 1980s left a deep mark on the Midwest. It was the worst downturn in farming since the Depression. After an unprecedented boom in demand for wheat ended, thousands of farmers faced ruin. Agricultural banks and makers of farming equipment were washed away by a wave of bankruptcies. Midwestern farmers look at parallels with the 1980s whenever their cyclical industry is heading downwards. Prices for corn, wheat and other agricultural commodities started to fall after their peak in 2013, since when the comparison has been raised again.

Exports of wheat and soyabeans nearly tripled in the 1970s, thanks to the weakness of the dollar after America abandoned the gold standard in 1971, and the Russian wheat deal in 1972, when America sold the Soviet Union about 440m bushels of wheat for around $700m. Until then the Soviets had imported hardly any American foodstuffs. The sudden bonanza was such that farmers bought more and more land, with more and more debt. This went well until interest rates jumped up, the dollar strengthened and exports to the USSR were halted after the invasion of Afghanistan. Farmers’ biggest asset, land, dropped in value, which in turn increased their liabilities until they became so big that they could not stay in business.

The latest farming boom started in 2006, when demand for crops such as maize (corn), sugar cane and soyabeans generated record profits thanks to demand for (maize and sugar-based) ethanol, and the then skyrocketing Chinese economy. American farmers again started to farm more land. They also used more yield-boosting technology—as did farmers in other parts of the world. A record 179m productive acres were brought in worldwide since 2006, says Dan Basse at AgResource, a research firm. Things started to turn sour after a year of record profits in 2013, when the rapidly growing global supply of grains outstripped demand, the appetite for ethanol stagnated and the Chinese economy slowed down. American net farm revenue dropped from $120 billion in 2013 to an estimated $62 billion this year.

But unlike the previous big crisis, the balance-sheets of many farmers are robust. Moreover, interest rates are still low and demand remains steady even if it isn’t growing much any more. And although the values for farmland dropped last year for only the second time since the 1980s, these drops were far less dramatic than they were back then: the value of land in Indiana, for instance, fell nearly 60% between 1981 and 1986. “This boom was not as strong and we don’t anticipate this crisis to be as severe as in the 1980s,” says Christopher Hurt at Indiana’s Purdue University.

Even so, farmers have reason to be anxious. The two things that matter most to them, weather and government policy, are unpredictable. “Monkeying around with trade deals makes us nervous,” says Brent Gloy, who farms in south-western Nebraska. America exports 20% of its farm production; its top export markets are Canada, China and Mexico.

Populist politics were born in a Midwestern farm-crash at the end of the 19th century. That 21st-century populism should come along at the same time as an agricultural slump is further proof of what Mark Twain knew: history rhymes.